This invention is directed to door assemblies, and in particular, it is directed to a skid plate for attachment to the bottom of a pre-hung door assembly whereby the attached skid plate provides a moisture barrier and prevents door bottom wear and/or damage during storage, handling and shipping of the manufactured door product.
Pre-hung door assemblies typically include a pair of doorjambs that extend between a header and a threshold often called a sill plate, a door secured in its closed position during shipping and handling, and exterior trim or molding such as brickmold or the like that is attached to each of the doorjambs, the trim being adapted to receive and finish-off masonry or siding material applied to the exterior of a building being constructed. The wooden members located in the bottom portion of door assemblies are often exposed to wet conditions, for example rain water, and rotting occurs along the lower portion of such doors. In particular, such wood rot conditions begin at the crosscut bottom ends of the doorjambs and exterior trim. This is because such exposed end grain has a tendency to absorb and wick moisture or water up into the long grain portions of the wood members, and over time, the resulting damp, wood rotting condition, will migrate into other adjacent wooden members along the door bottom such as wooden sill plates. Usual construction practice involves placing door assembly bottoms on concrete supports such as foundation walls or slabs. A protective coating such as paint or the like is then applied to the exterior surfaces of the jambs, header, trim, and door. However, such exterior protective coatings fail to solve the wood rot problems associated with the jamb and trim end grain supported on concrete surfaces. Concrete is a relatively porous material, and moisture, rain water, and standing water will actually travel through concrete and into the end grain where the moisture is wicked up into the long grain of the respective wooden members. This invention relates broadly to providing a moisture resistant skid plate attached to the bottom or threshold of a pre-hung door assembly to provide both a moisture barrier that prevents such wood rot.
After a pre-hung door assembly is manufactured, it is shipped from the mill to a dealer and then forwarded to a construction site where the door assembly is framed into a building under construction. Careless handling during the journey from the mill to the construction site often causes damage to the exposed end grain portions at the door bottom, such damage ranging from minor damage such as gouging, to major damage such as splitting that requires repair and/or replacement of the damaged jamb and trim. This invention also relates to providing a method for fixing a skid plate to a door assembly bottom to improve door bottom protection against wear and damage during storage, shipping, and handling from the manufacturing phase through final construction phase where the door is installed in a framing operation.
There have been various attempts in the past to overcome problems associated with shipping and installing pre-hung door assemblies. However, many of these earlier solutions fail to recognize the need to protect door bottoms from wood rot, and therefore, they only address the problem of mechanical damage. For example, in the past, wafer board skid plates were used to protect pre-hung door assembly bottoms from damage during shipping to the construction site. Wafer board skid plates are problematic in that they needed to be removed before the door assembly can be framed into a building. An even bigger problem associated with wafer board is that the material readily absorbs water and often disintegrates before the door assembly reaches the construction site. Additionally, wet wafer board will accelerate wood rot along the door assembly bottom if the wet material is left in place during storage.
U.S. Pat. No. 6,161,343 to Young recognizes wood rotting problems associated with exposed grain ends along door assembly bottoms. Young attempts to solve the wood rot problem by applying a sealant to the end grain portions and then covering the sealant with a plastic plate. The patent teaches applying various wood sealants to the end grain, the exemplary sealants including a conventional water seal of the type used on outside wood decks, a thick grease comprising a mixture of paraffin and petroleum jelly, and a preferred sealant of olefin wax such as paraffin. After the sealant is applied to the exposed doorjamb end grain a plastic plate is attached to the respective doorjamb end by nails driven into the end grain whereby the sealant is captured between the plastic plate and the crosscut end of the jamb. The teaching of the Young patent makes it necessary to individually seal and nail a plastic plate to each doorjamb end, and in instances where the door assembly includes exterior trim (brickmold), to individually seal and nail a plastic plate to each exterior trim end. A disadvantage of the Young teaching is that it requires a labor-intensive manufacturing process where each end cut member must be individually handled during a multi-step sealing and nailing process in order to protect all the crosscut door members from wood rot. Another disadvantage of the Young teaching is that end nailing the plastic plates to the doorjamb and trim pieces results in a weak connection that is easily separated during shipping and handling.
It is therefore an object of the present invention to provide a skid plate along a door assembly bottom to prevent structural damage to the door assembly parts during shipping and handling.
It is a further object of the present invention to furnish a skid plate along a door assembly bottom that provides a moisture barrier to prevent wood rot in the door assembly parts.
It is another object of the present invention to furnish a skid plate along a door assembly bottom that provides a moisture barrier for the doorjamb and exterior trim bottom ends to prevent wood rot.
It is an additional object of the present invention to provide an improved method for fixing a skid plate to a door assembly bottom.
In satisfaction of the foregoing objects and advantages, the present invention provides a skid plate and a method for attaching the skid plate to the bottom surface of a pre-hung door assembly to improve wear and moisture resistance. In one embodiment, the skid plate is formed from a generally rectangular sheet of material having a top edge; a bottom edge; first and second side edges extending between the top edge and the bottom edge; a first tab defined by a first portion of the top edge, a first portion of the first side edge, a first fold line extending from the top edge parallel to the first side edge and a first cut extending from the first side edge to the first fold line, the first cut being spaced apart from the bottom edge by a first distance; a second tab defined by a second portion of the top edge, a first portion of the second side edge, a second fold line extending from the top edge parallel to the second side edge and a second cut extending from the second side edge to the second fold line; a first slit extending from the bottom edge parallel to the first side edge and having a length greater than the first distance; and a second slit extending from the bottom edge parallel to the second side edge and having a length greater than the first distance.
A pre-hung door assembly according to a preferred embodiment of the invention includes a sill plate, first and second door jambs connected to the sill plate, first and second trim members having ends and being connected to the first and second door jambs, and a skid plate. The skid plate includes a first planar portion overlying the sill plate, first and second regions on the planar portion shaped to cover the ends of the first and second trim members, and a first tab normal to the first planar portion. With this configuration, the first and second regions are aligned with the ends of the first and second trim members when the planar portion overlies the sill plate and the tab overlies the first side. Alternately, the door assembly according to one embodiment of the invention can be described as including a first side, a second side, a bottom including a first section having a first shape and a second section projecting from the first section and having a second shape, a skid plate having a first portion shaped like and overlying the first section and a second portion shaped like and overlying the second section and at least one tab extending from the second portion and overlying a portion of the first side.